Illinois CPA firm licenses: ownership rules, restricted services and discipline records

What 225 ILCS 450 requires of Illinois CPA firms, which services only CPAs may do, peer review and how to read IDFPR records.

Illinois licenses CPA firms under the Illinois Public Accounting Act (225 ILCS 450), administered by the Department of Financial and Professional Regulation (IDFPR). This guide explains what the firm license means, what services are restricted to CPAs in Illinois and which aren't, and how to read the firm's record.

The firm license

IDFPR may license as licensed CPA firms "individuals or entities" meeting the requirements of 225 ILCS 450/14.4. The key ones:

• A majority of the firm's ownership, in financial interests and voting rights, must belong to people licensed or registered in some state.
• Partners, officers, shareholders or members whose principal place of business is in Illinois and who have overall responsibility for accountancy activities here must hold an Illinois CPA license.
• All owners, licensed or not, must be active participants in the firm or its affiliates.

IDFPR's public file lists these as "Public Accountant Firm License" and records the form of business: sole proprietorship, partnership or limited liability partnership, limited liability company, or corporation. We show that as the entity type on each listing.

What only CPAs may do

Illinois divides accountancy activities into three groups (225 ILCS 450/8.05):

1. Signing or associating a name with a report that expresses assurance on a financial statement, or an opinion based on an audit or examination: only licensed CPAs.
2. Other attestation engagements: only licensed or registered CPAs.
3. Accounting, management, financial or consulting services, compilations, internal audit, tax return preparation, tax advice, bookkeeping and representing taxpayers: not restricted to CPAs.

Section 8 adds that anyone who signs a name, including a trade name, to an audit or assurance report is deemed to be practising as a licensed CPA. In practice: a lender asking for "CPA-reviewed" or "audited" statements needs a licensed CPA firm; a business that only needs its books kept and its returns filed can lawfully use a non-CPA, though many owners prefer a CPA for the training and professional standards behind the title.

Licensed and registered CPAs

Illinois uses two individual credentials. A licensed CPA holds a license to practise and may sign audit and assurance reports. A registered CPA holds a registration: they passed the CPA exam and may use the title, but under Section 8.05 they may not sign audit opinions, though they may perform other attestation engagements. Passing the exam alone (a "certification") does not by itself confer the right to use the CPA title. When a firm tells you a CPA will lead your engagement, ask whether that person is licensed or registered, and look them up.

When the CPA title is used

Section 8.05(b) sets the restrictions for anyone offering or performing accountancy activities using the CPA title. A bookkeeping or tax business that does not call itself a CPA firm can lawfully prepare returns and keep books; one that uses "CPA" in its name or advertising is subject to the Act's licensing rules. If a business calls itself a CPA firm, it should appear in IDFPR's records.

Peer review

Under 225 ILCS 450/16(e), CPA firms and sole practitioners that perform the work in Section 8.05(a)(1) (audits and other reports expressing assurance on financial statements) must, as a condition of renewal, satisfactorily complete a peer review during the preceding three years, accepted by a peer review administrator, and make the documents available to IDFPR. Firms that don't do that work aren't subject to this renewal condition, and the statute lists other exemptions. If you're hiring a firm for an audit or review, ask for its latest peer review report and acceptance letter.

Discipline

IDFPR's licensing file records disciplinary actions against a firm's license: case number, action (such as reprimand, fine, probation or suspension), dates and a short reason. Most Illinois CPA firms have none. Where a firm has entries, we show them on its profile exactly as IDFPR publishes them. An entry is history, not necessarily a current restriction; the firm's current status is shown separately. Some entries relate to actions by other regulators, such as the Public Company Accounting Oversight Board, which oversees auditors of public companies.

If a firm's record shows an entry, ask the firm what happened and what changed afterwards. A clear, specific answer is a good sign; so is a long record with a single old entry. Several recent entries deserve more caution.

License dates

We show IDFPR's original issue date as "licensed since". Illinois firm license numbers begin with 066. Firms renew on a cycle set by rule; the expiration date in IDFPR's file is shown on each listing. A firm that changed its legal form (for example from a partnership to an LLC) may hold a newer license than its history suggests.

Checking a firm

1. Ask for the firm license number and the name of the Illinois-licensed CPA who will lead your work.
2. Search both on IDFPR's License Look-Up.
3. Read any disciplinary entries and ask the firm about them.
4. For attest work, ask for the peer review report.
5. Get an engagement letter that sets out the scope, responsibilities and fees.

What our Illinois listings include

We list firms based in Illinois whose firm license IDFPR shows as Active with an expiration date that hasn't passed. Firms based in other states that hold Illinois firm licenses, and individual CPAs, are not listed. IDFPR's file has the city, ZIP and county but no street address or phone, so firms can claim their listing to add contact details. The data comes from IDFPR's public licensing dataset, refreshed weekly here.

Updated 2026-10-16.

General information only, current as of the date above. The information on CPA Firm Check is not a recommendation or a guarantee of anyone's work. A license record shows registration status on the date shown, not workmanship, insurance coverage at the time of your job, or suitability for your project. Confirm license, insurance and permits directly before you hire. Rules and programs change; check the official sources linked in this guide.